LaFramboise W A, Standaert T A, Woodrum D E, Guthrie R D
J Appl Physiol Respir Environ Exerc Physiol. 1981 Nov;51(5):1169-74. doi: 10.1152/jappl.1981.51.5.1169.
End-expiratory airway occlusions were performed in eight unanesthetized premature newborn monkeys during acute hypoxemia to investigate mechanisms involved in the newborn's biphasic ventilatory response to hypoxia. Two-day-old monkeys demonstrated an immediate increase in minute ventilation (VI) and a decrease in PaCO2 followed within 5 min by a return of VI and PaCO2 to base-line levels. The decline in VI was associated with a decrease in tidal volume (VT) and inspiratory flow (VT/TI) and an increase in respiratory frequency. Occlusion pressures (PO.2) remained elevated throughout the hypoxic stimulus, and end-expiratory lung volume increased during the late response. "Effective" impedance (P0.1/V0.1, P0.2/V0.2, etc.) and "effective" elastance (Pmax/VT) were also elevated. At 21 days of age, the monkeys demonstrated a sustained ventilatory response as VI, VT, VT/TI, and P0.2 remained elevated throughout the period of hypoxemia. End-expiratory lung volume increases as on day 2, but effective impedance and effective elastance did not change. These data suggest that the biphasic response to hypoxia in the newborn may result from a change in respiratory timing and an alteration in respiratory mechanics and is not due to a decrease in central respiratory drive.
在急性低氧血症期间，对八只未麻醉的早产新生猴进行呼气末气道阻塞，以研究新生儿对低氧的双相通气反应所涉及的机制。出生两天的猴子表现出分钟通气量（VI）立即增加，动脉血二氧化碳分压（PaCO2）降低，5分钟内VI和PaCO2恢复到基线水平。VI的下降与潮气量（VT）和吸气流量（VT/TI）降低以及呼吸频率增加有关。在整个低氧刺激过程中，阻塞压（PO.2）持续升高，呼气末肺容积在后期反应中增加。“有效”阻抗（P0.1/V0.1、P0.2/V0.2等）和“有效”弹性（Pmax/VT）也升高。在21日龄时，猴子表现出持续的通气反应，因为在整个低氧血症期间VI、VT、VT/TI和P0.2持续升高。呼气末肺容积如在第2天一样增加，但有效阻抗和有效弹性没有变化。这些数据表明，新生儿对低氧的双相反应可能是由于呼吸时间的改变和呼吸力学的改变，而不是由于中枢呼吸驱动力的降低。
